package com.javacoo.xservice.base.utils;

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Random;

/**
 * UuidUtils
 * <p>说明:</p>
 * <li></li>
 * @author DuanYong
 * @since 2017年10月17日上午9:45:26
 */
public class UuidUtils extends Object {

	public String valueBeforeMD5 = "";

	public String valueAfterMD5 = "";

	private static Random myRand;

	private static SecureRandom mySecureRand;

	private static String s_id;

	/*
	 * Static block to take care of one time secureRandom seed. It takes a few
	 * seconds to initialize SecureRandom. You might want to consider removing
	 * this static block or replacing it with a "time since first loaded" seed
	 * to reduce this time. This block will run only once per JVM instance.
	 */

	static {
		mySecureRand = new SecureRandom();
		long secureInitializer = mySecureRand.nextLong();
		myRand = new Random(secureInitializer);
		try {
			s_id = InetAddress.getLocalHost().toString();
		} catch (UnknownHostException e) {
			e.printStackTrace();
		}

	}

	/**
	 * Default constructor. With no specification of security option, this
	 * constructor defaults to lower security, high performance.
	 */
	public UuidUtils() {
		getRandomGUID(false);
	}

	/**
	 * Constructor with security option. Setting secure true enables each random
	 * number generated to be cryptographically strong. Secure false defaults to
	 * the standard Random function seeded with a single cryptographically
	 * strong random number.
	 */
	public UuidUtils(boolean secure) {
		getRandomGUID(secure);
	}

	/**
	 * 随机生成GUID码
	 */
	private void getRandomGUID(boolean secure) {
		MessageDigest md5 = null;
		StringBuffer sbValueBeforeMD5 = new StringBuffer();

		try {
			md5 = MessageDigest.getInstance("MD5");
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}

		try {
			long time = System.currentTimeMillis();
			long rand = 0;

			if (secure) {
				rand = mySecureRand.nextLong();
			} else {
				rand = myRand.nextLong();
			}

			// This StringBuffer can be a long as you need; the MD5
			// hash will always return 128 bits. You can change
			// the seed to include anything you want here.
			// You could even stream a file through the MD5 making
			// the odds of guessing it at least as great as that
			// of guessing the contents of the file!
			sbValueBeforeMD5.append(s_id);
			sbValueBeforeMD5.append(":");
			sbValueBeforeMD5.append(Long.toString(time));
			sbValueBeforeMD5.append(":");
			sbValueBeforeMD5.append(Long.toString(rand));

			valueBeforeMD5 = sbValueBeforeMD5.toString();
			if(md5 != null){
				md5.update(valueBeforeMD5.getBytes());

				byte[] array = md5.digest();
				StringBuffer sb = new StringBuffer();
				for (int j = 0; j < array.length; ++j) {
					int b = array[j] & 0xFF;
					if (b < 0x10){
						sb.append('0');
					}
					sb.append(Integer.toHexString(b));
				}

				valueAfterMD5 = sb.toString();
			}

		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/*
	 * 转换成标准的GUID码例如: C2FEEEAC-CFCD-11D1-8B05-00600806D9B6
	 */
	@Override
	public String toString() {
		String raw = valueAfterMD5.toUpperCase();
		StringBuffer sb = new StringBuffer();
		/*
		 * sb.append(raw.substring(0, 8)); sb.append("-");
		 * sb.append(raw.substring(8, 12)); sb.append("-");
		 * sb.append(raw.substring(12, 16)); sb.append("-");
		 * sb.append(raw.substring(16, 20)); sb.append("-");
		 * sb.append(raw.substring(20));
		 */
		sb.append(raw);
		return sb.toString();
	}

	/**
	 * Demonstraton and self test of class
	 */
	public static void main(String args[]) throws Exception {
		UuidUtils myGUID = new UuidUtils();
		System.out.println(myGUID.toString());
		myGUID = new UuidUtils();
		System.out.println(myGUID.toString());
		/*
		 * Thread.sleep(10000); for (int i = 0; i < 1000; i++) { RandomGUID
		 * myGUID = new RandomGUID(); // System.out.println("Seeding String=" +
		 * myGUID.valueBeforeMD5); // System.out.println("rawGUID=" +
		 * myGUID.valueAfterMD5); // System.out.println("RandomGUID=" +
		 * myGUID.toString());
		 * 
		 * System.out.println(myGUID.toString()); //
		 * System.out.println(myGUID.toString().replaceAll("-", ""));
		 * 
		 * }
		 */
	}
}